Ring mill



Nov. 27, 1928. 1,693,247

J. MOLZ RING MILL Filed July 6, 1923 2 Sheets-Sheet 1 Fig. 1..

INVENTOR ATTORNEYS Nov. 27, 1928. 1,693,247

J. MoLz RING MILL Filed July 6, 1923 2 Sheets-Sheet 2 lNvENToR ATTORNEYS Patented Nov. 27, 1928.

UNITED STATES 1,693,247 PATENTjoFFIcE.

JOSEPH MOLZ, OF OBERHAUSEN, GERMANY, ASSIGNOR T THE BABCOCK & WILOOX COMPANY, OF BAYONNE, NEW JERSEY, CORPORATION OF NEW JERSEY.

RING MILL.

Application filedv July 6, 1823, Serial No.

The present invention relates to improvements in pulverizing fairly hard substances, such as coal and similar substances, and will be best. understood from the following de- .i scription and the annexed drawings, in which Figure l is a cross-section and Fig. 9. is a vertical axial section of a device embodying the preferred form of the invention.

Referring to the drawing, a ring 2 is mounted in a two-part casing 1. lili-thin this ring run three rollers 3, t ie spindles 3 of which are mounted in dust-proof bearing boxes 7. The latter are movable in radial frames 6 and are pressed outward by means of springs 8, each of which can be tensioned by means of bolts 9 and a spr-ino' plateV l0, so that the rollers may be pressed against the inner surface of the'ring with a pressure corresponding to the desired grinding pressure.

The frames 6 are fixed to hubs which are arranged on a central shaft- 4. Forming a part of the frame 6 is a sectional annular member' 6a having an inner flange 6*. The shaft 4 is mounted in bearings 20 and is driven by gearing 18, 19. Behind each roller is arranged a scraper shovel 11, secured in flange 6b, which is preferably arranged at an inclination and so formed that the. coal scraped of thereby during rotation, gradu- 3 ally falls through the space insideI the ring. The particles which have been sufficiently iinely ground are taken up by the current of air passing therethrough, and the pieces which are not sufficiently finely ground, fall back on the lower ring surface. Between the individual roller systems run conveying shovels or defiectors 12 arranged laterally from the ring, thesepshovels conveying the fuel dropping from the side of the ring back into the actual grinding system. The material to be ground is led to the ring track through an inlet 17 and an Opening provided in the ring., as shown by the arrow in Fig. 1. The material, on its ent-rance. is imm idiately seized upon by the firstroller and crushed against the ring, and` thus pulv'i'erized, it is taken up by the following shovel 11 and gradually shot through the space inside the ring to the lowest part of the ring track again.

Above the actual mill proper, and connected therewith, is a sifting chamber 13, which is connected by means of the suction branches 14 with a fan 15 arranged on the sifting chamber. It will be understood that 649,813, and'ineermany July 1o, 1922.

the cross-sectional area of the sifting chamber can be varied according to the degree of suitable ineness required, by means of shutters or valves. Theesifting chamber is con-- nectei'i to the actual mill by means of chutes 13, so that coa-rser parts separated in the sifting chamber can be led into the mill by way of these chutes.

On the right and left-hand ends of the mill are provided two inlet nozzles 16, through which the fan which is capable of regulation, dra through the mill, in the usual way, the air necessary for taking up the powdered fuel. This air preferably is-taken from the hollow spaces provided for cooling the burners. As it is consequently very hot, it serves, at the same time, when passing through the iilm of'pulverized coalL inside the mill, to dry this coal, so that, as a result, it

is possible to obtain a reduction by several per cent of lthe moisture content of the coal and special drying installations for the coal can be dispensed with if the moisture content of the coal is not too great..

Danger of explosion is out of theV question, as the mill is completelyclosed, and, moreover, the quantity of hot air introduced can be so regulated as by means of dampers 16` arranged inthe conduit leading to inlet nozzles 16 that an explosive mixture cannot be forme-d. f

The coal is predried in the usual way and fed in regulated quantities through' the inlet to the mill.

The construction shown in which a central opening is provided in the grinding surfaceof the ring permits material to be int-r0- duced directly onto the grinding surface and permits the fine material to be carried ofi', upwardly and out through the spaces between the grinding rollers. The heavier particles drop back onto the chutes 13 and are again fedl upon the grindinq surface of the ring. 1n this manner an eflicient separation of the fine material from the coarse is effected.

The ring may be provided with a second and preferably diametrically opposite inlet opening, and if that part of the ring surface which is doing the main portion of the work should become worn, then' it would only be necessary to turn the ring through 180 degrees about its horizontal axis, so that the other half of the ring would do the principal part of the grinding Work.

I claim:

, ring having an opening through the grinding Y i l. In a pulverizing mill, a stationary ring, a rotatable shaft, a frame carried thereby, rollers journalled in said frame and bearing against the ring,`annular flanges carried by said frame at the ends of said rollers, said surface thereof,'and means for admitting lm aterial to be pulverized therethrough.

`means for admitting material to be pulverized therethrough, a. housing surrounding said ring and rollers and means for admitting air to lsaid casing at the bottom of said ring.

3. In a pulverizing mill, a stationary ring, a horizontally Vdisposed rotatable shaft, a frame carried by said shaft, rollers journ alled in said frame and bearing against said ring to crush material against the same and Scrapers secured in said frame in the rear of and adjacent to said rollers, and acting against the grinding surface of the ring to remove material and drop it to Vanother part thereof.

4l. In a pulverizing mill, a stationary ring, a horizontally Vdisposed rotatable shaft, a frame carried by said shaft, rollers journalled in said frame and bearing against said ring to crush materialthereagainst, ascraper se- -curedin said frame and disposed behind and adjacent to each of said rollers, said scraper acting against the grinding surface of the f ring, to vremove material from the ring. and

todirect it into the path of another roller.

V5. In a pulverizing mill, a stationary ring, a rotatable shaft, a frame carried thereby, rollers journalledin said frame and bearing against the ring, the latter having an opening through the grinding surface thereof, means for admitting material to be pulverized therethrough, a housing` surrounding said ring and rollersi,'means for admitting air to said casing'at the bottom of said ring and means for withdrawing the air and finely divided material laterally of the ring through the spaces betweenthe rollers.

6. In a pulverizing mill, a stationary ring,

aY rotatable shaft, a. frame carried thereby,

Y rollers journalled in said frame and bearing against the ring, the latter having an opening tllrough the grinding surface thereof, means for admitting material to be pulverized th crethrough, a housing for said ring and rollers, means for admitting air to said casing at the bottom of said ring and means for withdrawing the air and finely divided material laterally of the ring through the spaces between tlierollers and a suction fan communicating with said housing above said ring.

7. In a pulverizing mill, a stationary ring, a rotatable shaft, a frame carried thereby, rollers journalled in said frame and bearing against the ring, the latter having an openingy through the grinding surface thereof, and means for admitting material to Ybe pulverized therethrough, said ring having a second opening in said ring substantially opposite said opening first mentioned whereby the main working surface may be changed by turning said ring until said second opening is in operative position.

8. In a pulverzing mill a stationary ring, a rotatable shaft, a frame carried by the shaft, rollers journaled in the frame, springs mounted on the frame forpressing the rollers against the ring, and means for admitting material to the surface of the ring through an opening therethrough to be pulveriaed by said rollers.

9. VIn a pulverizingmill, a stationary ring, a rotatable shaft, a frame carried thereby, rollers iournaled in said frame and bearing against the ring, annular flanges carried by said frame at theends of said rollers, and Scrapers carried by said flanges.

l0. In a pulverizing mill a stationary ring, a rotatable shaft, a vframe carried thereby, rollers journaled in the frame and bearing against the ring, means for admitting material to the surface of the ring through said ring to be pulver-ized by-the rollers, a casing surrounding the ring and rollers, means for admitting air to the casing at opposite sides of the ing at the bottom thereof, and means for withdrawing air and finely divided material from the casing at opposite sides of the ringat the top thereof. v

ll.V In a pulverizing mill a stationary ring, a rotatable shaft, a frame carried thereby, rollers journaled in said frame and bearing against the ring, annular flanges carried by the frame at the ends of the rollers, Scrapers carried by said flanges and lying in the path of travel of said rollers, and deflectors carried by said frame and lying out of the path of travel of said rollers.

l2. ln a pulverizing mill a. stationary ring, a rotatable shaft, radially disposed frame members mounted in pairs on the shaft in spaced relation, bearing boxes mounted in the frame members, a roller disposed between each pair of fra-me members and having a spindle journaled in said bearing boxes, springs for pressing the rollers against the ring, a housing enclosing the ring and thc frame members, and means for admitting material to the surface of the ring through the wall of the housing and through an opening in the ring for pulverization by said rollers.

JOSEPH ,MOXLZ- 

